The present disclosure deals in particular with noise reduction in a binaural hearing system in an asymmetric near-field environment, such as is e.g. present when a person engages in a telephone conversation, where a target sound is only audible on one ear, but the background noise is present at both ears. For a hearing impaired person wearing a hearing instrument at one or both ears, this situation is particularly challenging, but also provides possible options for improving the intelligibility of the target signal by appropriate signal processing of the signals received and/or picked up by the respective hearing instrument(s).
WO2006105664A1 deals with binaural hearing instrument systems comprising left and right hearing instruments including binaural processing circuits that generate left and right audio output signals, respectively, as a function of the signal-to-noise ratios (SNRs) of both the left and right audio input signals.
US2010111338A1 deals with a method of adjusting a signal processing parameter for a first hearing aid and a second hearing aid forming parts of a binaural hearing aid system to be worn by a user. The binaural hearing aid system comprises a user specific model representing a desired asymmetry between a first ear and a second ear of the user, e.g. defined by a discrete ‘synchronization mode’ variable, that controls the ‘overall amount of asymmetry’ in the binaural hearing aid system. As an example, a ‘high’ value of the synchronization mode variable will constrain the steering parameters to be very similar, whereas ‘medium’ and ‘low’ values will allow more deviations and finally ‘off’ will not synchronize the adjustments among the ears. The latter may e.g. be beneficial when picking up the phone (where the binaural hearing aid system should e.g. behave in an asynchronous mode).